This paper presents studies of permeabilities of three soil samples of widely differing properties at various degrees of saturation, various compactive efforts and various thixotropic strength ratios. The soils studied consist of a soft clay shale–attapulgite, a black cotton soil, and a lateritic kaolinitic soil. The results indicate the attapulgite to be the most structure sensitive and the lateritic soil the least structure sensitive. The permeabilities reflect these structural behaviours of the soils. Based on the test results, a practical back pressure is recommended for complete saturation of these compacted soils. The influence of moulding moisture contents on permeabilities are presented and values of thixotropic strength ratios for the three soils are also recommended.